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One of the most common reasons for failure in the marathon is suffering from muscle cramping. As many seasoned marathon veterans know, these muscle cramps can be one of most frustrating reasons for a poor performance. Typically, when you suffer from a cramp, everything else is going pretty well. The pace feels easy, you’ve got plenty of energy, and a new PR seems almost inevitable. Then bang! Your calf cramps and it takes everything you have just to crawl to the finish.

As we’ve been taught to do from the billions of dollars funneled into the sports drink market every year, most runners blame a lack of fluid or electrolyte intake for their untimely cramp. So, for their next marathon they work on drinking more often.

Unfortunately, as many marathoners know, this rarely solves the problem. It seems no matter how often we drink or how precisely we try to optimize our electrolyte levels, the same darn calf cramp returns late in race.

This is because your marathon cramping isn’t likely a hydration or electrolyte issue at all. Rather, the problem is what we call a “muscle overloading” or a fatigue cramp. This occurs when the neural mechanisms that are supposed to inhibit muscle contraction are depressed and the chemical and electrical synapses that fire the muscle fibers are enhanced. The result is an intense, sustained involuntary muscle contraction.

The question now is why do these fatigue cramps happen, even after running countless training miles, tough workouts and marathon-specific long runs?

Jeff Gaudette

Jeff has been running for 13 years, at all levels of the sport. He was a two time Division-I All-American in Cross Country while at Brown University and competed professionally for 4 years after college for the Hansons-Brooks Distance Project. Jeff's writing has been featured in Running Times magazine, Endurance Magazine, as well as numerous local magazine fitness columns.